The Consortium for Electric Reliability Technology Solutions (CERTS) Microgrid Laboratory Test Bed project's objective was to ease the integration of small energy sources into a microgrid. The project developed and demonstrated three advanced techniques, collectively referred to as the CERTS Microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of small generating sources. The following three techniques comprise the CERTS Microgrid concept:

A method for effecting automatic and seamless transitions between grid‐connected and islanded, or isolated, modes of operation.

An approach to electrical protection within the microgrid that does not depend on being triggered by abnormal electrical currents.

A method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high‐speed communications.

The project demonstrated these three basic techniques at a full‐scale test facility built near Columbus, Ohio, and operated by American Electric Power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers 1547 and power quality requirements. The electrical protection system distinguished between normal operation and situations when the grid experienced voltage and frequency stability problems. The controls were robust under all conditions, including difficult motor starts.

The project's test results should lead to the additional testing of enhancements to these three techniques at the test facility to improve the business case for microgrid technologies, as well to field demonstrations involving microgrids that involve one or more of the CERTS Microgrid concepts.

The objective of the CERTS microgrid test bed project was to enhance the ease of integrating energy sources into a microgrid. The project accomplished this objective by developing and demonstrating three advanced techniques, collectively referred to as the CERTS microgrid concept, that significantly reduce the level of custom field engineering needed to operate microgrids consisting of generating sources less than 100 kW. The techniques comprising the CERTS microgrid concept are: 1) a method for effecting automatic and seamless transitions between grid-connected and islanded modes of operation, islanding the microgrid's load from a disturbance, thereby maintaining a higher level of service, without impacting the integrity of the utility's electrical power grid; 2) an approach to electrical protection within a limited source microgrid that does not depend on high fault currents; and 3) a method for microgrid control that achieves voltage and frequency stability under islanded conditions without requiring high-speed communications between sources. These techniques were demonstrated at a full-scale test bed built near Columbus, Ohio and operated by American electric power. The testing fully confirmed earlier research that had been conducted initially through analytical simulations, then through laboratory emulations, and finally through factory acceptance testing of individual microgrid components. The islanding and resychronization method met all Institute of Electrical and Electronics Engineers Standard 1547 and power quality requirements. The electrical protection system was able to distinguish between normal and faulted operation. The controls were found to be robust under all conditions, including difficult motor starts and high impedance faults. The results from these tests are expected to lead to additional testing of enhancements to the basic techniques at the test bed to improve the business case for microgrid technologies, as well to field demonstrations in- volving microgrids that involve one or more of the CERTS microgrid concepts. Future planned microgrid work involves unattended continuous operation of the microgrid for 30 to 60 days to determine how utility faults impact the operation of the microgrid and to gage the power quality and reliability improvements offered by microgrids.